I just tore down 10 oil pumps (some OEM and some are aftermarket melling).

Two of the "stocker" OEM pumps I had have "star" type rotors in them instead of the typical 4 leaf "clover" configuration. What years did they do this? (The pumps had the larger cover plate with "prongs" to the top and right side and were the flat style with no "teardrop" lobes in the cover plate.)

Just Curious.

-D.Idiot

Oo, Oooo. Good question, DI. I just put one of these on my new 64 Dart motor, so I'm interested in history/trivia/pros-cons here...

Lou

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Home of Slant6-powered fun machines since 1988

The "g-rotor" type pumps were offered late in the SL6 production cycle.
Are the ones you found the 7/8 impeller thickness
(I have only seen these in 7/8 thickness... but you never know...)

Try this...
Get a "cloverleaf" and a G-rotor pump pump side-by-side. Make sure they both have the same impeller thickness. (7/8")
Spin both pumps by hand.
You will notice that it takes more force to spin a cloverleaf style pump...

The good news is that all the parts are interchangeable between housing so it's pretty easy to "mix & match" to get the combo you want.
DD

This is kind of where I was going on the teardowns, to put together a couple with good tolerances. I'll check the width on the impellers, just off hand they looked like they were the stock thickness (I'll finish cleaning them up tomorrow and post the findings).

Thanks!


-D.Idiot

Yep, they are 7/8" (or so...one is .825" not .875") thickness on the rotor dimension. Hopefully once I reassemble it will pass the clearance test (would prefer to use the 7/8" with easier rotational resistance than the Melling M66C I have sitting next to it...

thanks! (will have to keep an eye out for these since the local "pre-90's" pick-a-part get an occasional 80's slant six truck...)

-D.Idiot